User's Manual

Table Of Contents
Cinterion
®
ELS31-VA/ELS51-VA Hardware Interface Description
3.2 Power Up/Power Down Scenarios
76
ELS31-VA_ELS51-VA_HID_v01.000 2017-01-04
Confidential / Preliminary
Page 58 of 106
3.2 Power Up/Power Down Scenarios
Do not turn on the ELS31-VA/ELS51-VA while it is beyond the safety limits of voltage and tem-
perature stated in Section 2.1.2.1. ELS31-VA/ELS51-VA will immediately switch off when these
conditions are detected. In extreme cases this can cause permanent damage to the module.
3.2.1 Turn on ELS31-VA/ELS51-VA
ELS31-VA/ELS51-VA can be turned on as described in the following sections:
Connecting the operating voltage BATT_BB and BATT_RF (see Section 3.2.1.1).
Hardware driven switch on by ON line: Starts Normal mode (see Section 3.2.1.2).
After startup or restart, the module will send the URC ^SYSSTART that notifies the host appli-
cation that the first AT command can be sent to the module (see also [1]).
3.2.1.1 Connecting ELS31-VA/ELS51-VA BATT Lines
Figure 31 shows sample external application circuits that allow to connect (and also to tempo-
rarily disconnect) the module‘s BATT_BB and BATT_RF lines from the external application‘s
power supply.
Figure 31 illustrates the application of power using an externally controlled microcontroller. The
transistor T2 mentioned in Figure 31 should have an R
DS_ON
value < 50m in order to minimize
voltage drops.
Such circuits could be useful to maximize power savings for battery driven applications or to
completely switch off and restart the module after a firmware update.
After connecting the BATT_BB and BATT_RF lines the module can then be (re-)started as de-
scribed in Section 3.2.1.2.
Figure 31: Sample circuit for applying power using an external µC
3.8V
Module
Place C2-C5 close to moduleµcontroller
ENABLE
BATT_BB/RF
BATT_IN
C1
100nF
C2 47µF,X5R
C3 47µF,X5R
C4 47µF,X5R
C5 47µF,X5R
C6 47µF,X5R
R1
100k
R2
100k
R3
100k
R6
10k
T1
BC857
T2
IRML6401